How to insert item at the top of Combo Box?

Question

Hi I am using Linq to SQl to bind the combo box control. How can i add a item at the top of the list of combo box?

var items = from c in db.Contacts
                               orderby c.Name ascending
                               select c;
                if (items.ToList().Count > 0)
                {
                    cmb1.BindingContext = new BindingContext();
                    cmb1.DataSource = items;
                    cmb1.DisplayMember = "Name";
                    cmb1.ValueMember = "ID";
                }

                cmb1.Items.Insert(0, "--Select--");

This above code is failing.

Solution 1

One way would be to insert the "--Select--" contact place-holder into the results before binding:

     var items = (from c in db.Contacts
                  orderby c.Name ascending
                  select c).ToList();

     items.Insert(0, new Contact { ID = 0, Name = "--Select--" });

     cmb1.BindingContext = new BindingContext();
     cmb1.DataSource = items;
     cmb1.DisplayMember = "Name";
     cmb1.ValueMember = "ID";

Or you could do the same thing with an anonymous version of the results:

     var items = (from c in db.Contacts
                  orderby c.Name ascending
                  select new { c.ID, c.Name }).ToList();

     items.Insert(0, new { ID = 0, Name = "--Select--" });

     cmb1.BindingContext = new BindingContext();
     cmb1.DataSource = items;
     cmb1.DisplayMember = "Name";
     cmb1.ValueMember = "ID";

Solution 2

As you noted in your own comment to your question, you can't insert an item after data binding.

One option would be to use Concat to concatenate a sequence containing your "Select" item with the results of your query.